<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    .container{
      width: 100%;
      height: 200px;
      background-color: rgb(216, 211, 211);
    }
    .left, .right{
      width: 200px;
      height: 100%;
      background-color: rgb(167, 241, 126);
    }
    .content{
      height: 100%;
      background-color: #c954b7;
    }

    .container{
      display: flex;
    }
    .content{
      flex: 1;
    }
    .left{
      order: -1;
    }
  </style>
</head>
<body>
  <div class="container">
    <div class="content"></div>
    <div class="left"></div>
    <div class="right"></div>
  </div>
</body>
</html>